Ok. Actually I was gonna use Ai but read that McMillen's game were drawn in Flash (which I am not even sure) so I wasn't sure anymore what to use to get that result. So I'm gonna use Ai then.
I was thinking about a similar workflow to yours where I would sketch in Photoshop using my tablet and then vector it in Ai but that's for characters. Now, I'm really not sure how to do ground tiles with Ai... How do you do your ground and backgrounds?
Also, if you could quickly go over your Ai settings that would help me a bunch. Things like resolution, depth of color etc and how to save them in optimal quality for a video game.
One other thing is I read that XNA's exporter cannot really work with vectors so it converts them to PNGs so I was wondering why work with vectors if in the end your gonna end up working with non-scaleable assets. I have yet to do more research on this but if you know anything about it, let me know. We thought about building our own exporter but it would be a lot of work for now.
You work in a vector format and export as a .png spritesheet....so yes XNA reads .png spritesheets but you need to create them somehow, right? It's like saying "why would you work in .psd's when they'll eventually become .jpegs". You want to work in the editable format, save it FOREVER (because it's blasphemous to throw away source files D: ), and export as a .png.
You *definitely* want to keep the editable file. The way I work is I work in vector and I keep all my art assets as scalable as possible so that, when I'm mocking up game screens, I can easily move and shift things around without losing quality or having to rebuild things.
And you can definitely do the art in flash. People have done it, and it's not unheard of so don't think you're married to Ai.
I also don't have any special settings I've had to use....other than you should be using RGB instead of CMYK. :S (CMYK = print design only.)
Hope this helps! (And I welcome anyone to correct me! I've only worked for mobile games so I don't know if rules are different for different things.)